Debt - Additional Information (Detail)				12 Months Ended
	Oct. 30, 2017 USD ($)	Oct. 12, 2017 USD ($)	Oct. 05, 2017 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)
Line of Credit Facility [Line Items]
Debt instrument, collateral amount			$ 30,000,000
Debt instrument, additional collateral amount			10,000,000
Extinguishment of debt, amount				$ 10,049,000	$ 315,229,000	$ 58,220,000
Loss on extinguishment of debt, net				611,000	35,864,000	0
Accrued interest				1,489,000	1,585,000
Converted instrument, amount			579.77062
Deferred finance costs, net				1,058,000	1,633,000
Amortization of deferred financing fees				979,000	3,598,000	$ 4,002,000
Debt maturities, 2018				290,000
Debt maturities, 2019				0
Debt maturities, 2020				108,139,000
Debt maturities, 2021				0
Debt maturities, 2022				0
Debt maturities, thereafter				0
Senior Notes
Line of Credit Facility [Line Items]
Interest rate percentage	8.50%
Loss on extinguishment of debt, net					35,681,000
Write off of deferred debt issuance cost					5,416,000
Tender offer advisory services					$ 1,301,000
Senior Notes | Eight Point Five Zero Senior Secured Notes
Line of Credit Facility [Line Items]
Repurchased amount	$ 5,315,000
Extinguishment of debt, amount	5,928,000
Loss on extinguishment of debt, net	$ (524,000)
Convertible Debt
Line of Credit Facility [Line Items]
Repurchased amount		$ 1,077,000
Interest rate percentage					3.75%		3.75%
Extinguishment of debt, amount					$ 4,452,000
Principal amount of debt			$ 120,000,000				$ 125,000,000
Extinguishment of debt, amount					5,000,000
Loss on extinguishment of debt, net		$ (87,000)			183,000
Maturity date							Mar. 01, 2020
Initial conversion rate							40.8351
Principal amount of initial conversion rate							$ 1,000
Unamortized debt discount				$ 9,726,000
Effective interest rate				8.00%
Carrying amount of equity component				$ 16,847,000	$ 211,000
Percentage of principal amount redeemed					93.25%
Repayments of long-term debt, including payments for repurchase of equity					$ 4,663,000
Gain (loss) on early extinguishment of debt					110,000
Senior Secured Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity under term loan facility				50,000,000
Sublimit for letters of credit under line of credit facility				50,000,000
Tender Offer | Senior Notes
Line of Credit Facility [Line Items]
Extinguishment of debt, amount					245,604,000
Extinguishment of debt, amount					215,495,000
Unamortized premium					29,091,000
Accrued interest					1,018,000
Open Market Transaction | Senior Notes
Line of Credit Facility [Line Items]
Principal amount of debt					$ 9,750,000
Common Stock
Line of Credit Facility [Line Items]
Converted instrument, shares issued | shares			8.17192
Keybank National Association | Standby Letters of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity under term loan facility			$ 30,000,000
Current borrowing capacity				$ 14,072,000